User Manual
Slam Stick User Manual
Version No. 2.0
76
never be able to perfectly track the peak of long duration shock/acceleration events. At the end
of the shock event the output of the AC coupled accelerometer will produce an undershoot
(offset). These seemingly small amplitude deviations can result in significant errors during
numeric integration. The DC response accelerometers do not have this same problem because
it can follow the “slow-moving” input accurately. Check out our
that provides a quick overview of different accelerometer types and provides some
more information on integrating acceleration data.
What are the noise characteristics of the embedded accelerometers?
See the Component Datasheets and the Slam Stick datasheet for the frequency response of each
accelerometer/Slam Stick. The following three plots are FFTs of each of these accelerometers
when recording in a Slam Stick. There are some frequencies which will appear in a FFT because
of their noise levels.
Figure 34: An FFT of the ADXL345 (DC accelerometer in Slam Stick X and S, main accelerometer in Slam Stick C)
shows relatively good/low broadband noise levels. There is a noticeable spike around 25 Hz that appears inherent
to the digital component.
